This invention relates to a flexible pipe coupling. In another aspect, this invention relates to a pipe coupling which is insulated. In another aspect, this invention relates to a pipe coupling comprising an annular elastomeric seal assembly between an annular housing and a nipple which is partially submerged in said housing wherein said coupling is insulated in a manner to reduce the heat flow to the elastomeric sealing assembly from the fluid flowing through the pipe coupling.
High pressure, large diameter elastomeric pipe joints have been used as deep water drilling riser flex joints. The criteria for these units are high loads, high pressure, long life, and no maintenance. A problem has resulted, however, in the use of large diameter flexible couplings in offshore production risers. The problem lies in the fact that the sea water environment in which the subsea pipeline and riser are located has a temperature of about 40.degree. F. and the crude oil being produced through said riser and pipeline has a temperature of about 230.degree. F. When the line is not in service, it cools to the sea water temperature of about 40.degree. F. When it is in service, the warm crude oil temperature of about 230.degree. F. causes a growth in the length of the pipeline forcing some lateral movement in the riser which extends from the sea floor to the top of the off-shore platform, hence, the use of a flexible coupling. The flexible couplings, however, comprise elastomeric sealing assemblies which are also subjected to temperatures of about 230.degree. F. from the crude oil flowing through the pipe coupling. It is understood that no known elastomer can withstand a temperature of 230.degree. F. for 20-30 years, the lifetime desired for the coupling. It would be desirable, therefore, to design a coupling which can withstand the high temperatures of the crude oil and thereby satisfy the long life and no maintenance requirements of deep water drilling riser flex joints.
Accordingly, it is an object of this invention to provide an improved flexible pipe coupling.
Another object of this invention is to provide an improved flexible pipe coupling useful in offshore production risers.
Another object of this invention is to provide a flexible pipe coupling which can survive the high temperatures of crude oil encountered in offshore production for an extended period of 20-30 years.
Other aspects, objects, and advantages of the present invention will become apparent from a study of the disclosure, the appended claims, and the drawing.